Ventilation system for cooking unit



March 29, 1966 E. A. MALENCHINI 3,242,652

VENTILATION SYSTEM FOR COOKING UNIT Filed Feb. 18, 1963 2 Sheets-Sheet 1Ah? 1 J1] &/I/ 4). 0%

March 1966 E. A. MALENCHINI 3242 52 VENTILATION SYSTEM FOR ,cooxme UNITFiled Feb. 18, 1963 2 Sheets-Sheet 2 i I i United States Patent O3,242,652 VENTILATION SYSTEM FOR COOKING UNIT Emil Arthur Malenchini,Melrose, Mass., assignor, by

mesne assignments, to E. Van Noorden Company, Roxbury, Mass., acorporation of Massachusetts Filed Feb. 18, 1963, Ser. No. 259,005 4Claims. (Cl. 55-227) This invention relates to a ventilating unitadapted to remove grease and steam laden vapors from the vicinity ofcooking ranges, ovens, broilers, deep fat fryers, grills, and the like.More particularly it relates to a ventiliating unit adapted for use withcommercial or restaurant type cooking units, and provided with means forremoving grease from the vapors, means for cleaning the grease removingmeans, and means for inhibiting the spread of fires in the ventilatorand the attached flues and chimneys.

It is quite conventional to provide cooking units, especially the largerones used in restaurants and other commercial establishments with aforced ventilating system for the removal of the odors, vapors and heatcreated during cooking. Such vapors are normally laden with vaporized orentrained fats, greases and oils liberated during the cooking process orfrom frying units, especially deep fat frying units. Unless removed fromthe vapors these fats, oils and greases tend to condense on to thecooler surfaces of the ventilating unit and on the cooler surfaces ofthe flues, and chimneys to which the unit is connected. Theseaccumulations of fats, oils and greases are very inflammable and quitefrequently fires of destructive proportions occur in the duct work,fiues and chimneys associated with cooking unit ventilating systems.

It has previously been proposed to provide the exhaust side ofventilating units with filters or bafllles to remove the fats, oils,greases from the gas stream passing therethrough. To a degree thesefilters or baffies have been fairly successful. Clean filters, forexample, remove the fatty materials almost completely from the vaporstream. However, it is a dirty, messy job to remove and change thefilters, and frequently this job is postponed as long as possible, mostoften until the filters are so clogged that the air flow in theventilating unit is unduly impeded. In the meantime after a substantialquantity of oils and fats have accumulated in the filter there is atendency for this accumulation to revaporize, or to steam distill in thewarm vapors passing through the filter and in this way a proportion ofaccumulated fats and oils are transferred from the filter into the fluesand chimneys. Thus, a filter itself, if it is not changed or cleaned,frequently becomes a fire hazard since a dirty filter serves as arepository for fats and oils and does not necessarily prevent anaccumulation of fats and oils from forming in the fiues and chimneys.

Baflle systems suffer from the same basic deficiency. Since bafllesplaced in the exhaust air stream are relatively inaccessible they arediflicult to clean. As a result there is a tendency to permit the fattyoily deposits to accumulate facilitating the retransfer of thesedeposits to the duct work flue and chimneys. As in the case of filtersan oil and grease laden batfle does not prevent the accumulation of oilyand fatty deposits in the flue and chimneys and in addition may providein themselves a deposit of oils and fats suitable for spreading afire.

It is an object of this invention to provide a ventilating system withmeans for readily cleaning filters inserted in the air stream of theoily and fatty deposits contained therein, said means also acting toextinguish any fire that may start in said filter or in the duct work ofsaid ventilating system.

3,242,652 Patented Mar. 29, 1966 In the drawings:

FIG. 1 is a perspective view of a typical commercial cooking unitprovided with my improved ventilating unit;

FIG. 2 is a vertical cross-section of the ventilating unit shown in FIG.1.

In the drawing a typical commercial cooking unit is indicated generallyat 11 and as shown consists of two range units 12, a grill unit 13, adeep fat frying unit 14 and a broiler unit 15, together with appropriateovens indicated generally at 16. The selection and the arrangement ofthe particular units is a matter of choice and can be varied at willwithout affecting the operation or the principle of operation of thepresent invention.

Cooking unit 11 is provided with a ventilating unit indicated generallyat 21. Because of the dilferences in height and in the point of emissionof vapors, the ventilating unit 21 is made in a plurality of sections,one being a low level hood 22 adapted to be arranged over surfacecooking units such as 12, 13, 14 and 15, and the other being a higherlevel hood 23 adapted to be arranged above higher level unit, such asbroiler unit 15. Since, in the arrangement shown in the drawing, all of'the surface units are arranged next to each other, and

since the broiler unit is at one end of the cooking unit, only one ofeach of the two hoods is shown. Both hoods 22 and 23 are connected to acommon air chamber 24 which in turn is connected to a flue as indicatedby flue connection 25 located near the center of the top of chamber 24-.The flue connection 25 may be connected to normal duct work acting as aflue which may be either vented to the atmosphere outside the structureor be connected to a chimney in a conventional manner. An exhaust fan orblower is provided in the flue at some convenient location for thepurpose of inducing an air flow from the kitchen through the ventilatingunit out into the atmosphere. Neither the duct work nor the fan isshown.

The function of ventilating unit 21 is to collect the smoke and vaporscoming from the cooking units and to exhaust the smoke and vapors to theatmosphere. This is accomplished as mentioned above by maintaining apositive flow of air from the kitchen across the cooking unit and outthrough the ventilating unit and the flue. Unit 21 is adapted to rest onand be supported by cooking unit 11 by means of brackets as indicated byinturned flange 26 shown in FIG. 2, and to fit closely around the sidesand back of unit 11 as shown in order to direct the air flow in thedesired direction. Optionally the sheet metal comprising ventilatingunit 21 can be extended so that the unit can rest on the floorsurrounding cooking unit 11, or unit 21 may be mounted on a wall.

In the case of surface unit hood section 22 a continuous opening 27 isprovided along the length of the surface cooking units 12, 13, and 14and directly above these units at a point approximately midway betweenthe front and rear. Opening 27 of hood 22 is defined by horizontal shelf28 and baflie 29. Bafiie 29 in turn is attached to rear wall 31 ofsection 22. Opening 27 is purposely re stricted in order to maintain asufiicient air velocity through the opening and this restriction isaccomplished by provided baffle 29 which extends diagonally, upwardly'and outwardly from a point on rear wall 31 somewhat above the bottom ofrear wall 31 to a point below and slightly forward of the rear extremityof shelf 28. Shelf 28 in turn extends from a point above and rearward ofthe upper edge of baffle 29 horizontally to a point substantially towardthe front part of cooking unit 11. The height and width of shelf 27 andbaffle 29 are such that opening 27 is as close as possible to thesurface of the units comprising cooking unit 11 while at the same timeallowing suflicient clearance for the necessary pots and pans associatedwith cooking operations. A vertical air passage 32 is provided betweenopening 27 and air chamber 24 across the length of the surface units 12,13 and 14. Rear Wall 31 constitutes the rear wall of passage 32 and thefront wall 33 extends from a point at the top surface of shelf 28slightly to the rear of the forward extremity of baffle 29. The forwardwall 33 of vertical air passage 32 is provided with one or moretransverse openings which openings are provided with doors 34 which are,as shown, hinged at the bottom. Vertical air passage 32 terminates at apoint substantially longitudinal with the top surface of broiler unit inair chamber 24 which in turn extends laterally the full width of cookingunit 11. As shown, air chamber 24 is somewhat wider than air passage 32and comprises rear wall 31, top 35, front wall 36 and sloping bottomwall 37. Sloping bottom wall 37 extends between wall 36 and the frontwall 33 of passage 32. At the free end of cooking unit 11 a single sidewall 38 is provided for baffie 29, opening 27, passage 32 and airchamber 24. A portion of side wall 38 as shown (FIG. 1) extendsdiagonally downward from the front edge of shelf 28 to a point on theside of range unit 12 substantially forward of rear wall 31.

Hood 23 for broiler unit 15 extends above the top of the broiler unitfrom the forward wall 36 of air chamber 24 to a point substantiallyforward of the front of broiler unit 15. Hood 23 comprises top 41, twoside walls 42 (only one of which is shown) and a front 43. The outsideside wall (the one not shown) extends to the rear wall 31 and servesalso as a side wall for air chamber 24 at the broiler unit end ofcooking unit 11.

Hood 23 is provided with two transverse bafiles 44 and 45. Lower bafiie44 extends from rear wall 31 at a point above the top of broiler 15 to apoint slightly beyond the vertical projection of the front of broiler15. The forward end of bafile 44 is at a slightly higher level than therear portion and is provided with an upstanding lip 46. Upper baffle 45extends from rear wall 31 to a point within the lip 46 of bafile 44, theforward end of bafile 45 being at a slightly lower level than therearward end. For reasons to be explained later baffle 45 may beprovided with side walls 47 which extend horizontally at the level ofthe intersection of the top surface of battle 45 with rear wall 31. Aside wall 48 (which may be an extension of side wall 42) is providedinside air chamber 24 at the junction between broiler unit 15 and theremainder of unit 11 from the top of the broiler up to at least thelevel of upper baffle 44. Top 41 may be hinged at the rear to provideeasy access to the inside. Smoke and vapor coming from the broiler uniteither from the vent near the rear of the unit, or from the doors of thebroiler when they are opened are drawn forward between the top ofbroiler unit 15 and the bottom of bafile 44 around lip 46 and thenacross the top of baffle 45 to the chamber 24, then passing through theopening left above side wall 48.

Conventional grease filters 51 and 52 which may be formed from metalturnings or metal wool, or from glass or asbestos fibres retained in aframe are provided the entire width of vertical air passage 32 and theentire Width of the air passage between upper baffle 45 and top 41 ofhood 23 respectively. Filters 51 are wedged between rear wall 31 andextension 53 of shelf 28 at an angle of approximately 45 Access tofilters 51 is provided through doors 34. The filters 52 are supportedagain at an angle of about 45 on bracket 54 mounted on upper baflle 45in such manner that the upper and lower end of filter 52 are locatedslightly behind lip 46. Filters 51 and 52 respectively are arranged inside to side abutting relationship so that all of the air passingthrough ventilating unit 21 passes through one of the filter units.

The particular improvement contemplated in the present invention is theprovision of means for washing filters 51 and 52 which means also servesas an effective means for preventing the spread of grease fires in theventilating unit, the duct work and the fines. This means comprisesmanifolds'SS and 56. Manifold 55 is located in vertical air passage 32above filter 51, extends the entire width of passage 52 and is providedwith a plurality of spray nozzles 57 or the like arranged to provide aspray pattern that will cover the entire top of surface of filters 51.In a similar manner manifold 56 is located within hood 23 and the airpassage between top 24 and bafile 45 of hood 23, extends the full widthof hood 23 and is provided with a plurality of spray nozzles 58 or thelike arranged to provide a spray pattern that will cover the entire topsurface of filter 52,

Manifold 55 and manifold 56 are both connected to pipe 59 which in turnis connected to a hot water or steam supply indicated at pipe 61. Twoalternate means for admitting water or steam from pipe 61 to pipe 59 andthus two manifolds 55 and 56 are provided. A direct connection isprovided through normally closed solenoid actuated valve 62. Analternate connection is provided through parallel pipe loop 63 providedwith a manually operated valve 64 and between Valve 64 and pipe 59 witha detergent dispensing container 65.

Filters 51 and 52 may be cleaned periodically by opening valve 64 thuspermitting water or steam to flow from supply pipe 61 around loop 33past detergent dispensing container 65 into manifolds 55 and 56 outthrough nozzles 57 and 58 and onto filters 51 and 52. The detergentcontaining hot water or steam impinges on filters 51 and 52 in apressure spray pattern covering the entire surface of the filters andcleans the fat and grease collected in these filters quite effectively.

Provision is made for collecting the fat and grease containing water andremoving this from the ventilating inlet. In the case of surface unitsection 22 a trough 66 is provided within baffle 29. Trough 66 isarranged so that any water coming from filter 51 will be collectedtherein and will flow to a low point which is connected to drain 67. Inthe case of hood 23 bafile 45 acts as a water collecting tray in view ofside walls 47 and front lip 46. A drain 68 is provided between baffle 44and bafile 45 from the forward and lower end of bafile 45 to a pointoutside ventilating unit 21 where like drain 67 it can be run to aconvenient sink or wash basin and then into the sanitary plumbingsystem. It is preferable not to connect drain 67 and 68 directly to thesanitary system in order to avoid any possibility of a back fiow throughthe drain and also so that the wash water may be inspected visually. Innormal operation when the cooking unit is being secured from use theventilating fan is turned off and valve 64 opened for a few minutes, oruntil the wash water begins to turn clear. This can be done very easilyon a regular daily basis with practically no effort, and if doneregularly completely prevents the build up of any greasy or fattydeposits in the filters, ducts or flues.

As mentioned above, manifolds 55 and 56 also serve as a fire preventivemeans. A fire detecting thermostat 69 is provided in air chamber 24 withprobe 71 extending into the air stream and to line connection 25.Thermostat 69 is of the type that will either be actuated when the airtemperature reaches a predetermined temperature higher than theanticipated air temperature under normal operating conditions, or by anysudden rise in temperature. When actuated as by a fire thermostat 69closes the circuit which actuates the solenoid on valve 62 and opensvalve 62 and which disconnects the power supply to the exhaust fan. Thesudden flow of water or steam accomplishes two purposes. In the firstplace it acts as a sprinkler system quenching any fire in the greasefilter or in the lower parts of the ventilating unit. In the secondplace the water fills the voids in the filter thus cutting oif the airsupply and the oxygen supply to the duct work hues and chimneys. In theabsence of an air supply any fire in these areas quickly dies out.Unlike a conventional sprinkler system, however, as the water drainingout of filters 51 and 52 is immediately collected beneath the filtersand drained olf in drains 67 and 68 thereby avoiding any possibility ofwater damage to the range or the ventilating unit.

I claim:

1. In a ventilating system adapted to be arranged above a cooking unitin close proximity thereto and to remove from the surroundings thereofvapors and gases emanating therefrom, said ventilating system includinga ventilating duct for conveying a current of air, said duct includingan inlet portion located above said unit, and means associated with saidduct and remote from said inlet portion for inducing a current of air topass over said cooking unit through said inlet portion and out throughsaid duct, means for removing oil and grease from said current of aircomprising a flow-through grease filter comprising one or more filterelements each comprising a fibrous mat retained in a frame andpresenting a pair of substantially parallel planer surfaces adapted tointercept a fiow of air, said filter arranged across said duct from wallto wall thereof in a manner whereby any air passing through said ductpasses through at least one said filter element, said filter beinglocated in said duct as close to the said inlet thereof as practicable,said filter elements being so oriented that the planer surfaces thereofextend at an angle of about 45 to the vertical; a manifold mountedwithin said duct at a position above said filter, said manifold providedwith a plurality of spray forming elements and adapted to spray a hotliquid on said filter for washing oil and grease therefrom, said sprayforming elements forming a spray pattern of said hot fluid covering theentire exposed surface of said filter adjacent said manifold; and drainmeans within said duct below said filter for collecting said liquidafter said liquid leaves said filter and for removing said liquid fromsaid duct.

2. A ventilating system as claimed in claim 1 wherein said manifold isadapted to be connected to a source of hot water or steam.

3. A ventilating system as claimed in claim 2 wherein said manifold isconnected to said source both by a connector means including anautomatic valve and by a connector means including a manual Valve and asource of detergent.

4. A ventilating system as claimed in claim 3 wherein said automaticvalve is actuated by a fire detecting thermostat located in saidventilating duct and when actuated admits fluid to said manifold.

References Cited by the Examiner UNITED STATES PATENTS 1,895,618 1/1933Fedeler 242 X 2,024,122 12/ 1935 Wemhoener 55-242 2,633,929 4/1953 Farr55283 XR 2,889,007 6/1959 Lunde 553 17 FOREIGN PATENTS 903,457 8/ 1962Great Britain.

HARRY B. THORNTON, Primary Examiner.

1. IN A VENTILATING SYSTEM ADAPTED TO BE ARRANGED ABOVE A COOKING UNITIN CLOSE PROXIMITY THERETO AND TO REMOVE FROM THE SURROUNDINGS THEREOFVAPORS AND GASES EMANATING THEREFROM, SAID VENTILATING SYSTEM INCLUDINGA VENTILATING DUCT FOR CONVEYING A CURRENT OF AIR, SAID DUCT INCLUDINGAN INLET PORTION LOCATED ABOVE SAID UNIT, AND MEANS ASSOCIATED WITH SAIDDUCT AND REMOTE FROM SAID INLET PORTION FOR INDUCING A CURRENT OF AIR TOPASS OVER SAID COOKING UNIT THROUGH SAID INLET PORTION AND OUT THROUGHSAID DUCT, MEANS FOR REMOVING OIL AND GREASE FROM SAID CURRENT OF AIRCOMPRISING A FLOW-THROUGH GREASE FILTER COMPRISING ONE OR MORE FILTERELEMENTS EACH COMPRISING A FIBROUS MAT RETAINED IN A FRAME ANDPRESENTING A PAIR OF SUBSTANTIALLY PARALLEL PLANER SURFACES ADAPTED TOINTERCEPT A FLOW OF AIR, SAID FILTER ARRANGED ACROSS SAID DUCT FROM WALLTO WALL THEREOF IN A MANNER WHEREBY ANY AIR PASSING THROUGH SAID DUCTPASSES THROUGH AT LEAST ONE SAID FILTER ELEMENT, SAID FILTER BEINGLOCATED IN SAID DUCTS AS CLOSE TO THE SAID INLET THEREOF AS PRACTICABLE,SAID FILTER ELEMENTS BEING SO ORIENTED THAT THE PLANER SURFACES THEREOFEXTEND AT AN ANGLE OF ABOUT 45* TO THE VERTICAL; A MANIFOLD MOUNTEDWITHIN SAID DUCT AT A POSITION ABOVE SAID FILTER, SAID MANIFOLD PROVIDEDWITH A PLURALITY OF SPRAY FORMING ELEMENTS AND ADAPTED TO SPRAY A HOTLIQUID ON SAID FILTER FOR WASHING OIL AND GREASE THEREFROM, SAID SPRAYFORMING ELEMENTS FORMING A SPRAY PATTERN OF SAID HOT FLUID COVERING THEENTIRE EXPOSED SURFACE OF SAID FILTER ADJACENT SAID MANIFOLD; AND DRAINMEANS WITHIN SAID DUCT BELOW SAID FILTER FOR COLLECTING SAID LIQUIDAFTER SAID LIQUID LEAVES SAID FILTER AND FOR REMOVING SAID LIQUID FROMSAID DUCT.